One of the reasons we chose the AFR 225 heads was the availability of 72cc combustion cham
Those of you who have skipped ahead to the dyno results might be confused about now. Why would we dismiss the need for a 1,000hp build-up only to turn around and produce exactly that? Didn't we just say that it only takes 500 rwhp (600 flywheel) to reach 200 mph? What is the deal with all the extra power? Well, times have changed and so have our goals. Though the number of 200-mph street Mustangs is indeed rare, the simple fact that it can be done has already been proven. Rather than continue down that same "me-too" road, we decided to raise the bar and build not just a 200-mph 5.0-liter Mustang, but one that could achieve that speed in the standing mile.
Standing-mile competitions have become very popular, and for good reason. The format lends itself to impressive results without having to design a car to run flat out for 5 (in the case of Bonneville) or even 90 miles (Silver State Classic). Standing-mile competitions are a performance mix, combining both traditional quarter-mile drag racing with dry-lake or Bonneville top-speed runs. Getting a Mustang to run 200 mph is considerably easier than achieving that feat in just one mile. The horsepower requirements jump up considerably to say nothing of the traction and aerodynamics.
With our now-elevated bar, we immediately realized that just any old engine combination wasn't going to do.
Premium valvetrain components are a must on high-rpm small-blocks. The valves on our strok
Our first concern was the block, as making power is actually the easy part. Knowing this, we decided on a block from Dart Machinery. The Dart 8.2-deck block featured four-bolt splayed (steel) caps on the three center mains, with two-bolt caps being used on the outer two. Beefy 1/2-inch main bolts were employed, and the valley was machined to accept the factory hydraulic-roller guides and retainers. The Siamese cylinders measured a minimum 0.230 thick (at the maximum recommended 4.185 bore size), while the block also featured a true priority-main oiling system to ensure adequate lubrication at elevated engine speeds. To ensure proper sealing in high boost or cylinder-pressure applications, the Dart block featured a 0.625 deck surface and 1/2-inch (blind) head bolt holes.
As luck would have it, Dart supplied not only the perfect block, but the perfect short-block. Some time ago, Dart shipped one of its impressive SHP short-blocks, stuffed to the gills with all manner of forged internals. Since Dart offered the SHP short-block in a number of different configurations, we had to choose a suitable SHP candidate. Dart offered the SHP combination with the 302-based, 8.2-deck block in two different displacements. The displacement change was based on the bore size, as both the 347 and 363ci SHP short-blocks shared the same 3.40-inch stroke. The 347 utilized the smaller (more common) 4.030 bore, while the 363 stepped up to a 4.125-bore block. Dart offered both combinations with a cast-steel crank, though a 4340 forged-steel crank was an option. Regardless of the crank selected, both feature 4340 forged steel H-beam rods (I-beam rods were an option) and forged flat-top pistons. The pistons featured generous valve reliefs, deep enough (we discovered) for a 260-degree, 0.730-lift roller cam. Additional features in the SHP short-block included Hastings moly rings, Clevite rod and main bearings, and even coated cam bearings. Though not listed in the description, our short-block featured coated pistons as well. Basically the SHP short-block featured all the trick stuff you'd want if you were building one yourself. Knowing boost was in the cards, we elected to go with the 4.125-bore block, along with a forged crank, rods, and pistons.
Looking to shift power production higher in the rev range, we opted for a Box R intake sys
For maximum power, we chose the Box R upper intake. Note the two-piece design and generous
The Box R upper intake was designed to accept a 90mm throttle body. Our high-quality 90mm